Thou wilt come with half a call,
Spreading out thy glossy breast
Like a careless Prodigal;
Telling tales about the sun
When we’ve little warmth, or none.”
And one of the earliest parasitic fungi in spring is an Æcidium which flourishes on its glossy leaves. So common is Æcidium ranunculacearum on this species of Ranunculus, that it can scarcely have escaped the eye of any one who has taken the trouble to examine the plant. It appears in patches on the under surface of the leaves or on their petioles, in the latter case swelling and distorting them. Sometimes these patches are nearly circular, at others of very irregular form, and varying in size from less than one-twelfth of an inch to half an inch in diameter. It is found on several species of Ranunculus, as R. acris, bulbosus, and repens, but most commonly on R. ficaria. The leaf is thickened at the spot occupied by the parasite, and generally without indication on the opposite surface. Sometimes one spot, at others several, occur on the same leaf. The peridia are densely crowded together, often arranged in a circinate manner, i.e., like a watch-spring, or the young frond of a fern. The spores are orange, but slightly varying in tint on different species of Ranunculus ([Plate II.] figs. 12-14). One of the smaller clusters, when collected before the spores are dispersed, or the teeth of the peridium discoloured, mounted dry as an opaque object, makes a very excellent slide for an inch or half-inch objective; and the same may be said of many others of the same genus.
Less common than the foregoing is the species of Æcidium which attacks the violet. The sweetest of flowers as well as the earliest, in despite both of its odour and its humility, becomes a victim to one or more of the ubiquitous race of fungi. Thickened spots at first appear on the leaves; the petioles, or flower stem, or even the calyx, become swollen and distorted; and at length the cluster-cup breaks through. The spots on the leaves upon which the peridia are scattered are yellowish, generally larger than the clusters on the pilewort, and seldom with more than one spot on each leaf. The peridia, or cups, are irregularly distributed over the spots, not crowded together as in the last species; and the teeth are large, white, and distinct. The spores are at first orange, but at length become brownish. This species may be found in spring, as late as June, most commonly on the dog-violet, but also on other species of Viola.
It is not a very desirable occupation to search a bed of nettles, and turn over the individual leaves to look for minute fungi. A very pretty Æcidium is nevertheless far from uncommon in such a habitat. Fortunately it occurs very often on the petioles of the leaves and on the stem, distorting them very much; and in such situations flourishing, apparently, more vigorously than when occupying the under surface of the leaves ([Plate I.] fig. 10). In the latter situation the clusters of peridia are small, seldom exceeding a dozen in a spot, but several spots may be found on the same leaf. On the stem they are clustered around for upwards of an inch in length, and their bright orange colour in such a situation renders them very conspicuous objects. The peridia are always closely packed together upon a thickened base, and offer but slight variations from the forms already enumerated, save that they widen slightly at the mouth, so as to become nearly campanulate. The spores are orange, and very profuse.
During the past summer we noticed, for the first time, a very pretty little species of cluster-cup (Æcidium) on the wood sanicle (Sanicula Europæa) in Darenth wood. It was far from uncommon, and we believe it to be specifically distinct from its nearest ally, found on the earthnut leaves, and those of some other umbelliferous plants. The little cups are in small clusters of four or five together, on the under surface and on the petioles; they are small, but the teeth are relatively large, white, and distinct. The spores are of a pallid, yellowish colour, and not so profuse as in the last species. A darker spot on the upper surface of the leaf generally indicates their presence. This species was found many years ago by Carmichael at Appin, and called by him Æcidium saniculæ; but we find no notice of its occurrence since, though it seems to be far from uncommon at Darenth, and probably elsewhere, should the sanicle be common also.
Recently we found the bedstraw cluster-cup (Æcidium galii) on the great hedge bedstraw (Galium mollugo), and as it has not been figured before, we have included it amongst our illustrations ([Plate II.] figs. 15-17). Though very insignificant when occurring on the small leaves of the yellow bedstraw (Galium verum), it is a prominent object on the above-named species.